Peafowl hen with respiratory infection. Help

I have a 3 month old peahen that is half the size of her hatch mates. She is wheezing and has problems breathing. her body condition is poor and she seems somewhat bones. She acts the same as the other peafowl from her hatch. I have not noticed any discharge from her eyes but a little from her nostrils. Her feather condition seems alright and she seems to be eating and drinking okay. I put vitamins in the water and they are on a grow ration that I add a little soy meal to, too kick up the protein. When I listen with a stethoscope I hear rattling in her lungs. I have never had peacocks before and my not sure what to do.